Basal Ganglia

Question 1

What are the functions of the basal ganglia?

Answer 1

voluntary movements, procedual learning, habits, eye movements, cognition, emotions

Question 2

Which nuclei are forming the basal ganglia?

Answer 2

striatum (caudate nc and putamen, nc accumbens) globus pallidus (int. and ext.)

substantia nigra

subthalamic nucleus

Question 3

Which major diseases are related to disorders of the basal ganglia?

Answer 3

Parkinson disease: loss of dopaminergic cells in subst. nigra Huntington Disease: massive loss of medium spiny neurons in striatum

Question 4

What are the characteristics of medium spiny neurons?

Answer 4

>90% of all cells in striatum receives >10 000 cortical inputs per 1 MSN have GABA projection in Huntington Disease: massive loss of MSN

Question 5

How is the modulation of the basal ganglia on movements?

Answer 5

the output nuclei of basal ganglia are inhibitory suppresses activity in target regions the less output, the less inhibition

Question 6

What is the main difference between the direct and indirect pathway?

Answer 6

direct pathway: facilitates the correct movement (initiates movement), input is direct and robust indirect pathway: suppresses surrounding, competing movements (suppresses movement), input is widespread and diffuse

Question 7

How is the dopamine metabolism?

Answer 7

• Dopamine is formed from levodopa - is taken up into the synaptic vesicles, of not then it is metabolized via MAO - formation: tyrosine >> levodopa >> dopamine

Question 8

Which are the clinical sign of dopamine deficiency?

Answer 8

schizophrenia, AHDH, addiction, parkinsonism

Question 9

How are basal ganglia disorders characterized?

Answer 9

too much or too litte: - movement impulse - movement automatism - muscle tone

Question 10

How are extrapyramidal syndromes classified?

Answer 10

hypertonic-hypokinetic: incr. muscle tone, fewer movements hypotonic-hyperkinetic: decr. muscle tone, exessive movements

Question 11

What are the hyperkinetic movement disorders?

Answer 11

tremor, dystonia, athetosis, chorea, balism, tics, myoclonus, stereotypy, akhatisia, ataxia

Question 12

What are the hypokinetic movement disorders?

Answer 12

parkinsonism, catatonia, stiff syndrome, freezing phenomenon

Question 13

Akhatisia

Answer 13

general restlessness, reduced, when moving

Question 14

Ataxia

Answer 14

Incoordinated motor task

Question 15

Dystonia

Answer 15

Twisting movement at the peak of the movement, leading to abnormal posture

Question 16

Chorea

Answer 16

Irregular, unpredictible brief jerky movements

Question 17

Ballism

Answer 17

Irregular, purposeless rapid movement

Question 18

Myoclonus

Answer 18

Brief, sudden, shocklike movement

Question 19

Tremor

Answer 19

Oscillatory rhythmical, regular movement

Question 20

Bradykinesia

Answer 20

Slow initiation and progressive reduction in speed and amplitude of repetitive action

Question 21

what causes hemiballismus?

Answer 21

lesion of the basal ganglia, specifically subthalamic nucleus

due to:

• stroke
• trauma
• amyotrophic lat. sclerosis
• neoplasm
• demyalination
• post HIV infection